Author
Hiroshi Sagami
Bio: Hiroshi Sagami is an academic researcher from Tohoku University. The author has contributed to research in topics: Dolichol & Polyprenol. The author has an hindex of 23, co-authored 80 publications receiving 1270 citations.
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Papers
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TL;DR: Microsomal enzyme preparations from rat liver, brain, and testis catalyzed the formation of dehydrodolichyl diphosphates with the same chain lengths as those of the natural dolichols occurring in individual tissues.
74 citations
TL;DR: It is noteworthy that in spite of the similarity of the reactions catalyzed by these prenyltransferases, the modes of expression of catalytic function are surprisingly different, varying according to the chain length and stereochemistry of reaction products.
Abstract: Isoprenoids are the most diverse and abundant compounds occurring in nature. The study of isoprenoid biosynthesis began in order to increase our understanding of the process of cholesterol biosynthesis. The discovery of isopentenyl diphosphate (IPP), made independently by Lynen et al.(1958) and Bloch et al.(1959), opened the era of enzymatic studies on the fundamental chain elongation, which starts with the condensation between IPP and dimethylallyl diphosphate (DMAPP), with elimination of inorganic pyrophosphate. This chain elongation is interesting in that the reactions are regulated to proceed consecutively and terminate precisely at discrete chain lengths according to requirements of organisms. The chain length of the products varies widely from geraniol to natural rubber. In order to understand the mechanism of these reactions, it is essential to learn how many and what kinds of enzymes are involved in such chain elongation reactions.
59 citations
TL;DR: Results indicate that dolichol is formed from dehydrodolichl in rat liver microsomes, which is consistent with the results obtained under improved in vitro conditions with 10,000 x g supernatant of rat liver homogenates.
56 citations
TL;DR: Using a two-plate thin-layer chromatography method, polyisoprenoid alcohols (dolichols and polyprenols) of the rubber plant Hevea brasiliensis, and of ginkgo Ginkgo biloba and pine Pinus sylvestris are analyzed for dolichol occurrence in various tissues of different plants.
53 citations
TL;DR: Results indicate that the cell-surface glycoprotein of this halobacterium is modified with diphytanylglyceryl phosphate.
50 citations
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TL;DR: Results confirmed the earlier results obtained by incorporation of 13C-labelled acetate into the hopanoids of other bacteria and led to the identification of a novel biosynthetic route for the early steps of isoprenoid biosynthesis.
Abstract: Incorporation of 13C-labelled glucose, acetate, pyruvate or erythrose allowed the determination of the origin of the carbon atoms of triterpenoids of the hopane series and/or of the ubiquinones from several bacteria (Zymomonas mobilis, Methylobacterium fujisawaense, Escherichia coli and Alicyclobacillus acidoterrestris) confirmed our earlier results obtained by incorporation of 13C-labelled acetate into the hopanoids of other bacteria and led to the identification of a novel biosynthetic route for the early steps of isoprenoid biosynthesis. The C5 framework of isoprenic units results most probably (i) from the condensation of a C2 unit derived from pyruvate decarboxylation (e.g. thiamine-activated acetaldehyde) on the C-2 carbonyl group of a triose phosphate derivative issued probably from dihydroxyacetone phosphate and not from pyruvate and (ii) from a transposition step. Although this hypothetical biosynthetic pathway resembles that of L-valine biosynthesis, this amino acid or its C5 precursors could be excluded as intermediates in the formation of isoprenic units.
1,129 citations
01 Jun 1998
TL;DR: This review focuses on recent findings as to the structure and function of genes encoding nearly all of the enzymes required for the biosynthesis of these indispensable pigments and the enzymes they encode.
Abstract: Carotenoids are integral and essential components of the photosynthetic membranes in all plants. Within the past few years, genes encoding nearly all of the enzymes required for the biosynthesis of these indispensable pigments have been identified. This review focuses on recent findings as to the structure and function of these genes and the enzymes they encode. Three topics of current interest are also discussed: the source of isopentenyl pyrophosphate for carotenoid biosynthesis, the progress and possibilities of metabolic engineering of plants to alter carotenoid content and composition, and the compartmentation and association of the carotenogenic enzymes. A speculative schematic model of carotenogenic enzyme complexes is presented to help frame and provoke insightful questions leading to future experimentation.
942 citations
TL;DR: This review details the various facets of biotechnology of B. braunii, including its microbiology and physiology; production of hydrocarbons and other compounds by the alga; methods of culture; downstream recovery and processing of algal hydrocarols; and cloning of the algal genes into other microorganisms.
Abstract: Botryococcus braunii, a green colonial microalga, is an unusually rich renewable source of hydrocarbons and other chemicals. Hydrocarbons can constitute up to 75% of the dry mass of B. braunii. This review details the various facets of biotechnology of B. braunii, including its microbiology and physiology; production of hydrocarbons and other compounds by the alga; methods of culture; downstream recovery and processing of algal hydrocarbons; and cloning of the algal genes into other microorganisms. B. braunii converts simple inorganic compounds and sunlight to potential hydrocarbon fuels and feedstocks for the chemical industry. Microorganisms such as B. braunii can, in the long run, reduce our dependence on fossil fuels and because of this B. braunii continues to attract much attention.
742 citations
TL;DR: The algal biodiversity, the chemical structures and biosynthesis of hydrocarbons and ether lipids and the biotechnological studies related to hydrocarbon production are reviewed.
Abstract: This paper presents a review on Botryococcus braunii, a cosmopolitan green colonial microalga characterised by a considerable production of lipids, notably hydrocarbons. Strains like wild populations of this alga differ in the type of hydrocarbons they synthesise and accumulate: (1) n-alkadienes and trienes, (2) triterpenoid botryococcenes and methylated squalenes, or (3) a tetraterpenoid, lycopadiene. In addition to hydrocarbons and some classic lipids, these algae produce numerous series of characteristic ether lipids closely related to hydrocarbons. This review covers the algal biodiversity, the chemical structures and biosynthesis of hydrocarbons and ether lipids and the biotechnological studies related to hydrocarbon production.
734 citations
TL;DR: It is suggested that N-linked glycosylation in eukaryotes and in archaea share a common evolutionary origin and the function of the lipid carrier dolichol in oligosaccharide assembly is discussed.
655 citations